The invention relates to a wheel suspension for motor vehicles with level adjustment of the body.
From DE 30 37 179, it is known to protect the piston rod in a telescopic shock absorber arrangement for wheel suspensions of motor vehicles by means of an outwardly sealed, rubber-elastic bellows against dirt and moisture, wherein the interior space of the bellows is connected to an auxiliary volume. The auxiliary volume is formed by a cylindrical tube which is arranged around the shock-absorber tube of the shock absorber, or possibly directly formed onto the bellows.
DE 725 687 discloses a shock absorber arrangement for compensating pressure fluctuations within the bellows of two telescopic shock absorbers articulated in a housing, with the two bellows being connected together through a housing connection.
DE 102 00 608 A discloses a shock absorber arrangement in which the air space within the bellows is in communication with the surroundings through a line which ends in an air filter. During spring movements, air is either taken in or pushed out and passes through the air filter. The purpose is to prevent sand and/or dust particles from reaching into the interior of the space defined by the bellows. Sand would effectively act as a grinding paste between the spring washer and the spring winding. In that case, the spring would not reach its service life and would break prematurely.
The solution known from DE 102 00 608 A is sufficient for a simple system, essentially comprised of spring and spring washer. A disadvantage is the fact that the filter clogs sooner or later depending on the type of application, i.e. in what environment the motor vehicle moves. If there is no longer any free air passage, the bellows would substantially collapse or even burst. However, the biggest disadvantage is that the filter can no longer filter finer particles (smaller than sand). If this principle were to be used in a mechanical adjustment which, for example, includes a sensitive ball screw mechanism, this would not be sufficient. The grease of the ball screw mechanism may under no circumstances be contaminated because even finest particles would change the grease in its consistency so that the ball screw mechanism would be destroyed. Furthermore, the filter is not capable to keep away moisture, condensation water or splash water. Moisture would cause corrosion at the roller bearings and at the spindle/nut unit and would also destroy the ball screw mechanism.